


Private Annihilation

by croptopyeonbin



Series: Unfathom [2]
Category: TOMORROW X TOGETHER | TXT (Korea Band)
Genre: Aged-Up Character(s), Anal Sex, Biting, Blow Jobs, Bottom Choi Yeonjun, Butt Plugs, Human Choi Soobin, Human/Vampire Relationship, M/M, Semi-Public Sex, Top Choi Soobin, Vampire Choi Yeonjun, some mentions of food, soobin is a hot doctor and yeonjun rides a sexy motorcycle because i have no self control
Language: English
Status: In-Progress
Published: 2021-01-06
Updated: 2021-01-06
Packaged: 2021-03-16 20:42:34
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,000
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28588203
Author URL: https://archiveofourown.org/users/croptopyeonbin/pseuds/croptopyeonbin
Summary: “That was naughty of you,” Soobin says in a low voice. “Showing up at the clinic like that. Flaunting it in front of my clients.”“There have to be some benefits to being your sugar baby,” Yeonjun replies, mock-petulantly. “What’s the point if I can’t drop in and tease you at work? Anyway, you’re the real naughty one.”“Oh? How’s that?”A smile, with canines poking out. “You, gliding around that place like a cheap romance novel on legs. Talk about flaunting!”This is Yeonjun’s favorite game to play, and it’s not a game of cat and mouse. It’s a game for two cats.
Relationships: Choi Soobin/Choi Yeonjun
Series: Unfathom [2]
Series URL: https://archiveofourown.org/series/2094774
Comments: 16
Kudos: 131





	Private Annihilation

**Author's Note:**

> Read this first: 
> 
> \- this story contains depictions of an artificially large age difference. please keep that in mind, and do not read this if you are sensitive to that. to be clear: in this fic yeonjun is a 800+ year old vampire, but perpetually appears 22; soobin is around 40. they like to play around with people's assumptions of their relationship, which are all wrong. 
> 
> \- this is a sequel, so if you haven't read the first part of this series (Private Consumption), I recommend you do so before jumping into this one!

“Hi, baby,” Yeonjun says with a smile that Soobin could just barely make out between the gap of his eyelids.

“What time is it?” he asks, groggy.

“Almost seven.” Yeonjun lays back against the pillows and turns a page in his book. He is wearing a completely unnecessary pair of glasses, for no one’s benefit except Soobin’s. He does look good in them, though.

“You let me sleep in?”

“You seemed like you needed it after last night, old man.”

Soobin sits up with a groan. “I went from ‘baby’ to ‘old man’ in ten seconds, who says romance is dead?”

But it’s true, he’s not as young as he once was. That happens when you don’t immediately take up your vampire boyfriend’s offer to become an immortal being. And then continue dragging your feet on the decision for a decade and a half.

Yeonjun puts his book down and leans over to kiss his cheek. The joint of his glasses pokes perilously close to Soobin’s eye. “Thank you for not saying the thing about the pot, and the black kettle. I know I’m the real old man in this relationship.” Then he bounces out of bed, naked, showing off his firm, unchanging backside and legs.

Soobin stares. It’s difficult to get tired of the view.

Yeonjun jumps into a sweater and pair of jeans. “Come on, you perv. It’s time to get up and do your very important work, Dr. Choi,” he says with a smirk.

“And what will you be doing today while I’m off bandaging scraped knees and prescribing lice shampoo?” asks Soobin, not moving from beneath the comforter.

“Me?” Yeonjun leans over to look at himself in the mirror of their vanity. He picks up his favorite tube of lip gloss. Raspberry, with glitter. “I’m going to finish reading this book on quantum field equations. Someone has to find out what we immortals are going to do when the sun swallows up half the solar system, and I might as well be the one to figure it out. Luckily I’ve got a few billion years to do so–“

Soobin hauls himself up from bed. “You know, this is making your comment about my ‘important work’ sound awfully sarcastic.”

“– and then,” Yeonjun continues, ignoring his interjection, “I’m going to prepare for our special night.” He turns around to lean back against the vanity and smile at Soobin. The secret, knowing one.

The sight of it still drives Soobin a little crazy, in a dry-mouth, quickening-heartbeat sort of way.

“Care to give me a teaser?” he asks, raising his brow the way he knew Yeonjun liked.

“Absolutely not! Now go shower, or you’ll be late for all those sexy young moms begging you to figure out what’s wrong with their children.”

Soobin grumbles as he shuffles over to the bathroom, but not without giving Yeonjun’s ass a pat on his way there.

Haneul has big brown doe eyes with fat pockets of aegyo sal beneath. They're boast-worthy eyes, the kind all parents want to see creased back at them in a smile. Kids, Soobin thinks with wonder, represent all the potential of this world. Some things don't have an end, but everything has a beginning. 

"Feeling better, Haneul?" he asks. "No more tummy ache, I think." 

Haneul is too busy with her lollipop to respond, but she kicks her legs out happily. Good kid. 

Soobin turns to Haneul's mother, a woman in her early thirties with a well-tended bob and tasteful injections. "I think your daughter will be just fine, Ms. Lee," he says, pushing up his round glasses and trying hard not to glance down at his watch. "Just keep a closer eye on her eating habits this week and let us know if anything else comes up. But I believe she's fully recovered now." 

Ms. Lee is wearing a bright coral-pink lip stain. She already has her mouth open to respond when they are interrupted by a knock. 

"Dr. Choi?" asks a nervous voice on the other side of the patient room door. "There's... somebody who’s just arrived to see you." 

The tone of her voice tells Soobin everything. They both do a little bow, and Soobin leaves with a departing pat on Haneul's head. Outside of the patient room, he can tell his staff is trying hard not to glance out the window to the waiting room. Soobin smiles to himself. In his office, he swaps out his white coat for the long camel peacoat he'd worn to work that morning. He looks down, checks his dress shoes for water stains or errant splashes of vomit– the usual hazard of pediatrics. But by some miracle they are clean, the soft black leather shining faintly. It was a good purchase, an expensive one that he wouldn't have made for himself. 

On his way back out to the front, Soobin bows to his staff, tells them he's leaving for the day, and reminds them he won’t be coming in tomorrow. A polite chorus of "Goodnight, doctor," and "Thank you for working hard today," follows him out. 

In the waiting room, Soobin is greeted by a sight impossible not to smile at. 

It was always his dream to open a clinic after the drudgery of school and residency. He and Beomgyu used to talk about it drowsily, after the high of too many energy drinks faded while cramming in the study rooms at 3 AM. Now he has it, a small building but decently located, tucked into a sleepy side street off a major road in Yongsan-dong. Not really a fashionable place for a new practice, but somehow Soobin never had much trouble attracting clientele. It's odd, but he doesn't know any other pediatrician who treats as many small problems as he does; blisters and runny noses and other common occurrences which can easily be treated at home. His friends always have something to say about that, accompanied with winks and elbow jabs. 

"I don't think they come for your _medical_ _expertise_ , hyung," Beomgyu had snickered at their last reunion dinner. 

Even now, at the end of the day, his waiting room is bursting with fashionably attired Seoulite mothers and their children. But among all the Hermès and expensive haircuts, Soobin’s eyes are drawn to one point in the room. 

Yeonjun leans gracefully, casually, against the front door of the clinic. A vision in a motorcyclist’s one-piece suit, skintight to reduce drag. He’d gathered his blonde hair in a messy knot just above the neck. Nestled in his arms is a huge cluster of sunflowers wrapped in butcher paper, the petals so technicolor yellow that they wash out the rest of the room. 

After all the years they’ve spent together, Soobin still thinks time behaves a little differently when they meet eyes, and he can feel that they’re just standing there looking at each other a touch too long. One of his clients coughs politely into her fist. Yeonjun just smirks, letting Soobin drag out the moment.

“You’re early,” is what Soobin says after too many seconds of silence.

“I couldn’t wait that long to see you.”

Yeonjun glides toward him in that peculiar way of his. Floating, nearly.

“Happy anniversary, darling,” he purrs, too loudly, into Soobin’s ear.

A toddler starts wailing and it’s almost enough to drown out the tide of silent disappointment in the room. Handsome, unmarried Dr. Choi with a successful medical practice. He’d hit 40 with a full head of hair, no hint of a beer gut, and a steadfast reputation. Good target for a fling or at least some flirting, it was said in certain circles. Soobin suspected some of his own nurses fanned the flames. He didn’t put a stop to it, because this was the sort of guerilla marketing any new business would pay for.

Leave it to Yeonjun to behave territorially. How endearing.

And how inconvenient.

“We were supposed to meet at the restaurant,” Soobin chides in a whisper, without bite.

Yeonjun says nothing. He doesn’t need to.

The sunflowers are too heavy to bring with them; they were just for show, anyway. Soobin leaves the bouquet with his receptionist and her moony-eyed gaze.

“Put that in some water, please,” he asks. “And then on my desk.”

Most of his clientele end up trickling out of the clinic behind them, a little exodus of sighs and catty side glances at Yeonjun, whose hand slithers into Soobin’s coat pocket with a not-quite-imperceptible simper. Soobin indulges him. Yeonjun only unglues himself from his side to bring out a helmet from beneath the seat of his motorbike.

“Here,” he says, coming toward Soobin with the helmet. He stands on tiptoe to place it over Soobin’s head, gently drawing it down and adjusting the straps. This close, Soobin can see how carelessly Yeonjun’s chignon is held up with a few pins. Glitter bounces tiny refractions of light from beneath his eyes.

Yeonjun disengages the kickstand, swings one long leg over the saddle of his Ducati Superleggerra, hooks his chin over a shoulder, and looks back at Soobin.

“What are you waiting for? Climb aboard, doctor.”

They go with the chef’s prix fixe tasting menu. When the waiter waltzes away with their order, having pretended not to stare at Yeonjun the entire time, Soobin leans forward.

“That was naughty of you,” he says in a low voice. “Showing up at the clinic like that. Flaunting it in front of my clients.”

Yeonjun swishes the wine in his glass and does a convincing job of pretending to sip at it. But then, he’s had a lot of time to practice. “There have to be _some_ benefits to being your sugar baby,” he says, mock-petulantly. “I loved you even when you were just a poor student. What’s the point if I can’t drop in and tease you at work? Anyway, you’re the real naughty one.”

“Oh? How’s that?”

A smile, with canines poking out. “You, gliding around that place like a cheap romance novel on legs. Driving those poor nurses and mothers out of their minds with your carefully calibrated sexy doctor act. Talk about flaunting!”

Yeonjun tosses his head, careful to let the solitaire studs in his ear wink by candlelight. They were a gift six anniversaries ago: 2.54 carats, brilliant white, set in platinum. Soobin had spent a long time looking at them before he decided, yes, he was going to buy those diamonds.

He leans back in his seat.

This is Yeonjun’s favorite game to play, Soobin knows, and it’s not a game of cat and mouse. It’s a game for two cats.

“Are you hungry?” he asks.

“Yes. I’ve been starving for this.”

On cue, the appetizer course arrives: Regiis Ova caviar, with a tiny persimmon pudding chaser in its own ramekin.

Soobin picks up his fork. “We should both dig in now, hm?” He glances down meaningfully, then back up again.

“Certainly.” Holding Soobin’s gaze, Yeonjun slowly picks up his own fork, and then lets it drop to the floor with a clatter and a smirk. “Oops.”

Shivers. But Soobin thinks he hides it well.

“You should pick that up,” he suggests mildly. “The waiter probably won’t circle back to our table until this is finished.” He gestures at the appetizer plate on the table. “And I intend to take my time enjoying this meal.”

“As do I,” says Yeonjun, sinking down in his seat.

He folds his limbs under the long white tablecloth. It’s a tight fit down there beneath a table for two, especially at his height. But Yeonjun stays down. That will be his battlefield.

Soobin feels a hand on each knee parting his legs. Warm palms press their way up his thighs, slowly, until they reach the intersection of his hips. Soobin eats some caviar as Yeonjun’s clever fingers work at opening his belt, button, and zipper. It’s light grey beluga sturgeon roe. Buttery. Soobin enjoys it.

When Yeonjun has created a path through all the layers, he leans his head against Soobin’s inner thigh and just… exhales. His breath is cold on the bare skin of Soobin’s crotch, and Soobin freezes. One hand moves down blindly, beneath the cover of the tablecloth, to stroke Yeonjun’s hair. At this touch, Yeonjun practically purrs. He rubs his cheek against the skin of Soobin's upper thigh before giving it a lick followed by a loud, messy suck.

Soobin pushes the caviar around mindlessly on his plate, his whole body tensing up as Yeonjun worries at that spot with blunt teeth and tongue in succession. And then, just as he’s thinking of giving that hair an impatient little yank, Soobin feels it– a tiny prickling sensation, two sharp points piercing skin. It’s pleasurable on its own, spiked with only the smallest bit of pain. Makes him feel all loose and game for anything.

But what really has Soobin holding back a low groan is knowing how the bite affects Yeonjun. He needs less and less blood these days, but he drinks just as often as he used to because it feels _good_. And because Soobin lets him, and the knowledge of that willful acquiescence is its own high for them both.

Soobin lets his legs fall further apart in encouragement, and Yeonjun moves closer to fill in the space. Now that he’s just drank, his body feels noticeably hotter even through their clothes. His hands, when he lifts up Soobin’s very interested cock, are warm.

But it’s nothing compared to the liquid heat of his mouth as Yeonjun takes in the beginning of him. Soobin jolts in his seat with surprise; no slow, teasing grip of the fingers to start. Just the tight suction of Yeonjun’s lips around the head of his cock. And then, Yeonjun’s tongue working insistently against his slit, coaxing him to full hardness right away, wet and messy.

Soobin’s fingers tighten in Yeonjun’s hair, pulling close to the roots. His hips jerk forward, and Yeonjun moans just a little too loudly, vibrating around him. If he could look at Yeonjun right now, crouched beneath the table, he knows what he’d see: flushed cheeks, pink on cream like a peach just beginning to ripen. Big wet-looking eyes, and lips plump with blood.

A stray, wild thought occurs to him: _flip the table_.

Let everyone in this ridiculous, pretentious restaurant see Yeonjun just as he is now, kneeling on the floor with his head between Soobin’s legs, having cock stuffed through his fat lips into that gorgeous, unbelievable mouth.

The idea of it is enough to have Soobin closing his eyes, almost seeing stars. He rocks forward as subtly as he can in his seat. Yeonjun lets him, holding himself still to be fucked into.

Soobin is close. He’s so gut-wrenchingly, lip-bitingly wound up he could burst. He can feel Yeonjun’s tongue on him, pushing against his cockhead, impatient and maddening around the most sensitive part of his body. Soobin bites off a grunt, thrusts forward.

Yeonjun sucks him down, and Soobin is right there, just right––!

But then… Yeonjun pulls off his cock, breaking the tight seal of his mouth with a loud, wet pop impossible for anyone within a few feet not to hear. Soobin startles as he feels Yeonjun move away; he cuts off an indignant, disbelieving gurgle from his own mouth. His fingers catch on Yeonjun’s hair for just a second, and then open to let him slip away.

When Yeonjun gracefully reemerges in his seat, his lips are shiny and swollen. He makes a show of licking them as Soobin stares, blood pounding.

“I found this appetizer a little… wanting. Didn’t you?” Yeonjun asks, nonchalantly.

Soobin can barely hear him. He’s still reeling, _pulsing_ in his seat.

Yeonjun reaches up to finger the loosened pins in his hair, dislodged from their place by Soobin’s pulling. “You should call for the next course while I go fix my hair in the restroom.”

Jaw hanging open, Soobin watches as Yeonjun pushes his chair back and gets to his feet. He’s all long, svelte limbs, encased in unforgiving white mesh and neoprene. Absolutely tight all over. No secrets under that outfit.

When Yeonjun walks past him, he places a gentle hand on Soobin’s shoulder. “Don’t forget to zip yourself back up before you stand, big boy,” Yeonjun whispers in to his ear. “I don’t want everyone else seeing what’s mine.”

Good call. Soobin stuffs himself back into his pants as surreptitiously as he can, while craning his head to watch Yeonjun saunter off to the restroom. And in this restaurant he’s not the only one watching him walk away on those legs. That outfit is a menace. When Yeonjun disappears beyond the door, some of those heads swivel around to stare at Soobin.

He knows what it looks like. Wealthy middle-aged man, shamelessly chasing a young piece of tail. So desperate he can’t even keep his hands off of him in a public place. Exactly what Yeonjun wants people to think.

If only they knew. It’ all true and yet, still only half the story.

Soobin is painfully hard in his trousers. But he waits what seems like an unsuspicious amount of time before he stands up and follows.

Yeonjun is standing at the mirror, actually fiddling with his hairpins. Soobin can tell he’s already touched up his lip gloss. They stare at each other for a moment through the mirror.

Then, Soobin reaches out a hand, curls it around Yeonjun’s wrist. He draws them together with slow purpose.

“Open your mouth,” he says.

Yeonjun smirks at him, lips closed.

“Open it,” Soobin repeats.

This time he obeys, letting his tongue hang out past the rim of his bottom lip.

Soobin doesn’t kiss him so much as he tries to devour him. He pushes Yeonjun back up against a stall, the better to leverage his tongue and teeth against Yeonjun’s own. There’s no resistance at all; he is warm, pliant, soft between the wall and Soobin’s own body.

“What do you want of me?” Soobin asks, cupping that little vixen face. His thumb traces the edge of a glittering diamond stud. “What can I give you?”

Yeonjun grabs him by the collar. His eyes are dark and they glimmer under the fluorescent lighting. “I want you to belong to me forever,” he says, no hint of play left in his voice. “The way I can only belong to you.”

Soobin knows what Yeonjun is saying. He nods. “Yes. Yes,” he murmurs along Yeonjun’s neck.

They shove themselves into one of the stalls. With hasty hands, Yeonjun unzips the top of his rider outfit and pulls it off his shoulders. The one-piece suit bunches around his waist until Soobin spins him around to face the wall and pushes the material further down to his thighs. Yeonjun is wearing black bikini-cut panties. Basic, unassuming. Still sexy.

“Go on,” he says in a rush. “There’s a little something–“

Soobin sticks two fingers beneath the band and yanks the panties down.

There is _something_ : the crown of a plug nestled snugly between Yeonjun’s cheeks, a little wet around the rim. Not a toy he’s seen before.

“Oh,” says Soobin intelligently. His brain is so fuzzy. Then, “Is that new?”

“Brand spanking new,” Yeonjun replies with an impatient little shake of his ass.

Soobin’s hand looks absurdly large curled around one cheek, his thumb pushing lightly against the top of the plug. It’s shaped like a glass fox. Actually, a _kumiho_ , Soobin realize when he takes a closer look. Nine tails flare out behind the fox’s body, wide enough as a base to prevent the whole thing from sinking in, like a hilt on a sword.

Soobin’s mouth starts to water. He alternates little pushing and pulling motions on it, fucking him slow and wet and smooth, and before long Yeonjun is panting, one cheek pressed against the stall, eyes screwed shut.

“Faster,” Yeonjun hisses. “Weren’t you ready to blow when you followed me in here?”

“Shh. I said I wanted to take my time tonight.”

One of Yeonjun’s hands gropes backward, pushing Soobin’s fingers aside. He slides the plug out of himself with a whimper and a slick, gloopy noise. The toy is a decent size, especially in Yeonjun’s palm. It’s beautiful, like a luxurious centerpiece with a lurid secret. Yeonjun turns himself around and slips the glistening plug into Soobin’s jacket pocket. 

Soobin _tsk_ s. “Really? This is Valentino.” 

“Come on, where else am I supposed to put it?” Yeonjun asks, batting his eyes. “I want the real thing.”

Soobin kisses him. Here, in this restroom with his clothes down around his ankles and his lip gloss smudged across cheek and chin, Yeonjun is ancient and glorious and _he wants Soobin_. The many years they’ve spent together do nothing to reduce the marvel of it all. Soobin won’t make him wait one moment longer.

He pulls off the rest of Yeonjun’s motorcyclist suit and unzips himself. Then he hikes up one of Yeonjun’s ridiculous legs around his waist, angling him open. Yeonjun scrambles to hold onto the top of the restroom stall behind him as Soobin carefully rocks up into the tight, wet crevice of his body.

“Ahh, finally,” he sighs. “The main course.”

Soobin laughs at that, and then Yeonjun is giggling too, a cute breathy sound as he pulls himself up and down on Soobin’s cock using his grip on the top edge of the stall as leverage.

“Do you think,” he huffs, “they know what we’re doing in here?” His voice is hopeful.

Soobin laughs again, this time against the warm flushed skin of Yeonjun’s neck. “Yeah, I think everyone got the idea.”

Yeonjun preens, throwing his head back. His hair is all messed up again. Hopeless, really. He’s so yielding around Soobin, all soft heat and rocking hips. Soobin kisses him again; he can’t get enough. It’s all so easy, touching him. The most natural thing in the world. The right thing. Every stretch of skin familiar and precious. Every muscle hardening under pressure, like the diamonds in his ears. Yeonjun’s closed his eyes, and his breath is uneven. Soobin knows this is when to pick up the pace. He pounds in and out, fast and shallow.

“Oh,” Yeonjun exhales, bouncing against the wall. “ _Ohhh_.”

After that, no more words. His whole body jerks and tenses, completely outside of his own control. Back arched, mouth wide open, he comes. Yeonjun is so loud like this, and his cock shoots off all over the front of Soobin’s shirt.

Soobin holds him close, thrusts in deep through the slick clench and just grinds there against him. Yeonjun cries out, too sensitive, tries to wiggle up and off of him. He’s whining as Soobin chokes through his own orgasm, every neuron focused on the searing pulse of Yeonjun’s body around him. 

When Yeonjun can stand again, they untangle and fix themselves shakily. Soobin’s shirt is ruined, but almost all the mess can be hidden when he buttons his suit jacket. Yeonjun quietly asks for his plug, and Soobin pushes it back into him.

When Yeonjun has poured his body back into that tight one-piece, he turns around. “I meant what I said earlier.”

“I know.” Soobin knows exactly. “I said yes then, and I said yes tonight.”

“I want you to belong to me, the way I can only belong to you,” Yeonjun repeats himself.

“I do already.” This is the most redoubtable principle of his life; Soobin considered it more serious than any wedding vow. It’s the truest thing he could ever say.

“I can wait forever,” Yeonjun emphasizes, with a hard look. “But you can’t.”

Soobin tenderly zips up the front of Yeonjun’s rider suit. “I know,” he says again. Once, he had made a promise, and he’s kept Yeonjun waiting for a long time. He places a hand on Yeonjun’s chest, over where his heart would beat if it still could. “I’m almost ready.” 

**Author's Note:**

> happy georgia run-off! idk what it is, but elections always got me closing out my wips... must be the adrenaline lol
> 
> something i'm interested in as a writer is exploring power reversals. i started writing Private Consumption as a smutty one-off, but then realized i wanted it to be a bit more. hence in chapter two i reveal that yeonjun has been hibernating, and is such a newborn in the modern world. this puts him, an incredibly powerful figure, on his back foot and creates a reliance on human soobin. and there's also such a vulnerability to yeonjun's fear of losing this person who is so fragile compared to himself. 
> 
> here, i wanted to explore a different sort of power balance. i am SO wary of large age differences because 99% of the time it's just predatory behavior. but i liked the idea of using yeonjun's immortality to flip that schema on its head; to the world, yeonjun appears so much younger and ripe for victimhood. in actuality, he is anything but!
> 
> [twt](https://twitter.com/croptopyeonbin)


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